Expression pattern of somatolactin in the Chinese sturgeon, Acipenser sinensis Gray, 1835

Somatolactin (SL) is a pituitary hormone specific to fish and is reported in a variety of teleost species. Although it appears to be involved in many different physiological processes, its biological functions are poorly understood in Acipenseriformes. In this paper the expression pattern of this protein is characterized in Chinese sturgeon (Acipenser sinensis). Structure analysis showed that AsSL had a 24aa signal peptide and a 208aa mature protein, one N-glycosylation site at positions 145-147 and seven Cys residues conserved with other SLs. The antiserum was raised against a 15 aa antigen, derived from the Chinese sturgeon somatolactin (AsSL) amino acid sequence. Western blot analysis showed the pituitary-specific expression of AsSL. In situ hybridization revealed that the mRNA of AsSL was expressed mainly in pars intermedia (PI), although also slightly in proximal pars distalis (PPD), cells expressing AsSL disperse throughout the pars intermedia. These findings provide useful information for future physiological research in Chinese sturgeon